HK1185158B - Reduced-contact or contactless force transmission in a clock movement - Google Patents

Description

Force transmission device with reduced or no contact in a timepiece movement

Technical Field

The invention relates to a method for manufacturing a transmission device with controlled or reduced contact or no contact in a timepiece movement.

The invention also relates to a timepiece movement comprising at least one pair of components made or modified by implementing the method described above.

Background

The present invention relates to the field of watchmaking, and more specifically to the field of mechanical movements.

The frictional behaviour of the components of a clockwork has a direct influence on the dimensioning, the performance, the quality of operation, the regularity of the speed and the lifetime thereof.

Friction leads firstly to a loss of efficiency, which entails increasing not only the size of the energy storage means, such as mainsprings and the like, but also the size of the means for transferring the above-mentioned energy within the whole mechanism. This results in a larger section and diameter than necessary for the operation of the timepiece. Naturally, the greater the friction, the greater the effect on the autonomy of the timepiece, and the lower the power reserve.

Wear affects all components that are subjected to friction, impact stress or high contact pressure. Wear is a recurring problem, and long-term wear leads to deterioration of the quality of the movement, particularly in terms of isochronism. Although wear involves all the moving parts of the movement, it mainly involves the components and the timing elements of the escapement, the toothing of the blades and pinions, as well as the arbour and the pivot.

It is known to minimize friction using a suitable surface treatment. In fact, the feasibility of lubrication is very limited in the watchmaking field and cannot be optimally used for long-term action.

It is also contemplated to minimize the actual contact by eliminating contact or by reducing the length of contact or by reducing the contact pressure.

Attempts have been made in the field of power transmissions to eliminate any contact by means of magnetic type solutions using a pivotal drive driving a first driven receiving wheel or pinion, comprising a magnetized surface, by means of a second driving transmitting wheel or pinion, driven by an energy source and also comprising a magnetized surface, wherein the first and second wheels or pinions approach each other in a joint plane as described in CN patent No. 200610112953.2 in the name of li linger group or in a substantially tangential direction as described in the same document, or even in a more complex spiral geometry as described in JP patent No. 0130332 in the name of Shoei Engineering Co Ltd.

Combinations of ring gears and magnetic surfaces for transmission applications or electromechanical power machines are described in GB patent No. 2397180 in the name of Newman and CN patent No. 2446326 in the name of qianhui. In CN patent No. 2446326, each tooth of the wheel comprises two sectors of different polarity on either side of a radial line, said sectors being arranged opposite similar sectors of the opposite wheel of the same polarity, their toothing interacting.

As regards the support, radial magnetic levitation supports are known from CN patent No. 2041825 in the name of south china trade company in the tobacco market, or axial and radial magnetic levitation supports are known from JP patent No. 7325165 in the name of Seikosha KK.

Since the 17 th century, for example, due to the achievements of Adam Kochanski, the watchmaking field has become familiar with magnetic stops for limiting the travel of the balance and thus making the balance spring redundant.

However, in the above-described methods, the use of a large number of solid magnets results in a large space requirement, as well as complexity in manufacturing the components.

Disclosure of Invention

The object of the present invention is to overcome all or part of the above drawbacks, by providing a method for manufacturing timepiece movement components or a method of modifying such components so as to limit or eliminate any contact between the opposite parts while ensuring their operation.

The invention therefore relates to a method for manufacturing a transmission device with controlled or reduced contact or no contact in a timepiece movement, characterized in that the manufacturing or modification of at least one pair of opposite surfaces, called cooperating surfaces, of the same member or of a pair of opposite members of said timepiece movement is achieved by subjecting at least one of said opposite surfaces forming said pair to a surface treatment or an integral treatment to impart an electrostatic and/or magnetic charge thereon, wherein one of said surfaces drives the other or abuts against the other, so that one of said surfaces tends to repel the other opposite surface of said pair when said surfaces are moved closer to each other.

According to one feature of the invention, the manufacture or modification of said at least one pair of opposite cooperating surfaces of the same member or of a pair of opposite members is achieved by subjecting said opposite cooperating surfaces to a surface treatment or an integral treatment to impart to them electrostatic and/or magnetic charges of the same polarity and/or magnetism, such that they tend to repel each other when said opposite surfaces are moved closer to each other.

According to a feature of the invention, each of the opposed cooperating surfaces is subjected to a surface treatment or an integral treatment when the opposed surfaces are manufactured or modified.

According to a feature of the invention, during said surface treatment, said surface is covered with at least one thin layer, called activation layer, of charged or magnetized particles having the same polarity or the same magnetic properties as each other, so that when said counter-cooperating surfaces are moved closer to each other, they tend to repel each other, or at least one such thin activation layer is created.

According to another characteristic of the invention, the surface treatment or the overall treatment consists in: a plurality of thin layers of pairs of charged and/or magnetized particles of the same polarity or the same magnetism are created or deposited on each of the opposing cooperating surfaces such that they tend to repel each other when the opposing cooperating surfaces are moved closer to each other.

Advantageously, according to the above method, any friction between the members forming the pair of mutually cooperating opposite members on at least one cooperating surface of one of the members and on at least one opposite cooperating surface of the other member is reduced or eliminated.

According to a feature of the invention, said thin layer is arranged to generate at 0.1mC/m²And 50mC/m²An electret layer of surface charge density in between.

According to a feature of the invention, said surface treatment or integral treatment consists in generating or depositing on said cooperating surface or on said counter-cooperating surface at least one thin magnetically active layer having a remanent magnetic field Br greater than or equal to 1T and a coercive excitation Hc greater than or equal to 100 kA/m.

According to another characteristic of the invention, the thin layer comprises at least one fluorinated polymer film.

According to another characteristic of the invention, the thickness of said thin layer is less than or equal to 20 μm.

The invention also concerns a timepiece movement including at least one pair of opposed members, one of which drives the other or abuts against the other, said pair of members being made or modified by implementing the method described above.

The present invention provides the following advantages: the thickness of the thin layer is sufficiently small that it does not change the dynamic characteristics, so that it makes it possible to maintain the dimensions of the components.

The combination of a friction layer and a specific configuration of the opposing surfaces, which friction is controlled by repulsion or attraction between the opposing surfaces, provides good control of friction and good mechanical efficiency with minimal wear.

Further features and advantages will be apparent from the description given below only by way of non-limiting example.

Detailed Description

The present invention relates to the field of watchmaking, and more specifically to the field of mechanical movements.

The invention therefore relates to a method for manufacturing a transmission with controlled contact, in particular a transmission with reduced contact or a contactless transmission in a timepiece movement.

According to a preferred embodiment of the invention, the manufacture or modification of at least one pair of opposite surfaces, called cooperating surfaces, of the same member or of a pair of opposite members of said timepiece movement is achieved by subjecting at least one of said opposite surfaces forming said pair to a surface treatment or an integral treatment to impart an electrostatic and/or magnetic charge thereon, wherein one of said surfaces drives the other or is in close proximity to the other, so that one of said surfaces tends to repel the other opposite surface of said pair when said surfaces are moved closer to each other.

In a particular implementation of the invention, the manufacture or modification of said at least one pair of opposite cooperating surfaces of the same member or of a pair of opposite members is achieved by subjecting said opposite cooperating surfaces to a surface treatment or an integral treatment to impart to them electrostatic and/or magnetic charges of the same polarity and/or magnetism, such that they tend to repel each other when said opposite surfaces are moved closer to each other.

Any friction between the members forming the pair of opposing members is reduced or eliminated during the implementation of the method. The members cooperate with each other via at least one cooperating surface of one member and at least one opposing cooperating surface of the other member.

In short, the pair of opposite members is protected by reducing friction, as is the case for the whole timepiece movement.

The method may be applied when manufacturing the component or when changing the component. The term "manufacturing" is used indiscriminately in the following two cases.

For example, in a preferred and non-limiting application, the pair of opposing surfaces or opposing members may comprise:

-two gears;

-two cams;

-a cam and a rocking lever;

-two oscillating levers;

-a spindle or shaft and a pivot;

-a pallet and an escape wheel;

-a pallet fork and a balance roller;

-a wheel and whip;

-a heart cam and hammer;

two consecutive coils of the same spring, in particular a thin spring or a hairspring;

star wheels and fingers.

According to a feature of the invention, preferably, when a pair of opposed surfaces is manufactured or modified, each of the opposed cooperating surfaces is subjected to a surface treatment and/or an integral treatment.

When the pair of opposing surfaces is subjected to a surface treatment, each opposing surface is covered with at least one thin layer of charged or magnetized particles, called activation layer, having the same polarity or the same magnetism as each other, so that when these opposing cooperating surfaces are moved closer together they tend to repel each other, or at least one such thin activation layer is created.

When the pair of opposing surfaces is subjected to an integral treatment, a part of the structure of each member concerned is subjected to an electrochemical treatment and/or a magnetization treatment on at least one thin layer, called activation layer, which after said treatment comprises charged or magnetized particles having the same polarity or the same magnetic properties as each other, so that when these opposing cooperating surfaces are moved closer together they tend to repel each other, or at least one such thin activation layer is created.

Naturally, according to the present invention, one of the opposing surfaces may be subjected to surface treatment while the other opposing surface is subjected to integral treatment, or both of the opposing surfaces may be subjected to surface treatment, or both of the opposing surfaces may be subjected to integral treatment.

The concept of charged or magnetized particles is also applicable to the growth of crystals made of at least two elements that are not individually charged or magnetized but are charged or magnetized at the time of crystal growth. The concept is also applicable to the deposition of charged or magnetically charged particles that are activated or immobilized by heating.

The above-mentioned activation layer may be activated, for example, especially a magnetization layer; or the above-mentioned active layer is activatable, i.e. activated after its production or deposition, in particular an electret as will be seen below.

In particular, the surface treatment consists in: a plurality of thin layers of pairs of charged and/or magnetized particles of the same polarity or the same magnetism are created or deposited on each of the opposing cooperating surfaces such that they tend to repel each other when the opposing cooperating surfaces are moved closer to each other.

In particular, in a similar way, the overall process consists in: these thin layers are produced over the entire component. The whole treatment is as follows: subjecting a portion of the structure of each member concerned to an electrochemical and/or magnetizing treatment on a plurality of thin layers comprising, after said treatment, pairs of electrically charged and/or magnetically charged particles of the same polarity or the same magnetic polarity, so that when said opposite cooperating surfaces are moved closer to each other they tend to repel each other.

Although the preferred embodiment of the invention is directed to surface treatment of all or part of the opposed cooperating surfaces, it will be apparent that the desired effect may be achieved by the overall treatment. However, because the other components of the timepiece movement are not intended to be disturbed, the overall treatment is not always possible, which is why the case of the surface treatment is described more specifically herein. The surface treatment may involve one or several outer peripheral layers of the relevant component. The multi-layer treatment may allow for the generation of more uniform forces that are more stable over time and less dependent on small local variations in charge or magnetic field strength.

It is therefore clear that although a small layer is considered an advantageous solution, since it is directly compatible with existing components with their tolerance gaps, such a thin layer is a preferred solution and not the only one that can be used to implement the present invention.

According to the fine-machining method, the thin layer is a charged layer subjected to an electric force, in this case called an electret, or the thin layer is a thin magnetized layer subjected to a magnetic field force, or the thin layer is a thin layer charged and magnetized at the same time. When the thin layer is magnetically charged, it is preferably made in the form of a hard magnetic material, such as neodymium iron boron or the like. "magnetic charge" refers to a non-point-like magnetic dipole, although it may be of small size.

In the practice of the invention, at least one layer of the type described above is activated so that the layer imparts the required polarity or magnetic properties thereto. In the case of electrets, the layers or members are electrochemically treated at high electric field strengths and possibly in combination with heat treatment and/or contact with liquids.

As regards the magnetization layers, at the end of the deposition process some magnetization layers are already polarized on the cooperating surfaces, the other magnetization layers have to be polarized after the end of the process. One particular polarization method consists in: the structure is placed in a laser field that creates a disturbance, allowing the particles to be easily oriented under the influence of an external magnetic field.

In a particular embodiment, after deposition, at least one thin layer of the type described above is activated on the cooperating surface in order to impart the required polarization or magnetization.

With regard to the above-mentioned activation, the person skilled in the art can refer to the teaching suggestions in the sensor, activator, storage disk or antenna industry, which use thin layers and whose processing has been the subject of publications that can be directly applied here.

For charged thin layers or electrets, the following articles can be cited, in particular with regard to "corona" type activation.

"Non-contact electrically micro-bearing using polymer electric" published by Mr. Yukinori Tsuurumi, Yuji Suzuki and Nobuhide Kasagi of the mechanical engineering department of Tokyo university, Proc. IEEE int. Conf. MEMS 2008, Tucson,2008, pp 511-514 ";

mr. Edamoto, Y.Suzuki and N.Kasagi of the mechanical engineering department of Tokyo university and K.Kashiwagi of the research center of Asahi Glass Corporation of Shennaii county, Mr. Morizawa, and T.Yokohama, T.Seki and M.Oba Mr. 978-1-4244 and 2978-3/09 of the core technology center of Omron Corporation of Kyoto2009IEEE, pp 1059-1062, published as Low-resonant-frequency micro electretgenerator for energy harvesting application》；

Mr. 978-1-4244-2978-3/09 of microsystem engineering systems (IMTEK) of Freiburg university, Germany, J.Gaspar and O.Paul2009IEEE, pp1043-1046, A2D electric-based resilient micro energy harvetter.

For the magnetic thin layer, the following articles can be cited in particular:

-IFW Dresden S.Neu, M.Weisheit, U.Hannemann, S.Leinert, A.Singh, A.Kwon, S.Melcher, B.Holzapfel and L.Schultz, High Performance maps published in 18th Workshop on High Performance maps and the hair applications, Annecy France 2004, pp 566 & amp 576;

mr. I.Betancourt and H.A.Davies, of Department of Engineering Materials of University of Sheffield UK, material Science and Technology,2010, Vol 26, No 1, pp 5-19,2010 Institute of Materials, Minerals and Miners, "Exchange coupled nanocomposite hard magnetics".

Preferably, in a first embodiment, the thin electret layer is charged (ion or electron injection, "corona" method, by liquid contact, or other method), said thin layer being arranged to produce about 10mC/m²And advantageously at 0.1C/m²To 50mC/m²Surface density of electric charge in the range of 10mC/m²For example, allows to obtain a value of greater than or equal to 10 μ N/mm for a distance of greater than or equal to 100 μm²The electrostatic force of (2).

In the case of electrets, the active layer is electrically polarized and may be formed from SiO₂、As₂S₃Polymers (e.g., PET), fluorinated polymers (e.g., Teflon, or a combination thereof,<<Asahi>>Is/are as follows<<>>、<<Speciality Coating Systems>>Of parylene) And (4) forming. Parylene or the like may be deposited to accommodate a surface at ambient temperature.

In a particular embodiment, the at least one thin layer is SiO on a silicon substrate₂An electret.

SiO₂The layer may be produced by oxidation of silicon in an oxygen atmosphere furnace or in the form of a deposited layer.

The charged active layer can optionally be enclosed between two metal layers each having a thickness between 10 and 1000nm, or be arranged on the periphery of the component on top of a single metal layer having a thickness between 10 and 1000nm, in both cases the total thickness of the active layer and the metal layer preferably being less than 20 μm. The member itself may also be electrically conductive.

The electrostatic charge can be transferred to an embedded insulator such as SiO in a similar manner to EEPROM type electronic memories₂Of (e) a polysilicon layer. Islands of arbitrary size can be formed by photolithography as used in microelectronics and the like)。

In a second embodiment of the invention, the thin layer is magnetized, the surface treatment or the integral treatment preferably consisting in generating or depositing on the cooperating surface and/or the opposite cooperating surface and preferably on both, at least one thin magnetically active layer having a remanent magnetic field Br of about 1T, substantially greater than or equal to 1T, and a coercive excitation (excitation) Hc of hundreds of kA/m, substantially greater than or equal to 100 kA/m.

Depending on the particular case, the polarization is carried out parallel to the plane or perpendicular to the plane. The tangential moment action produces either a repulsive or an oppositely attractive effect, which is required to practice the invention. For polarization perpendicular to the plane, there is repulsion if the magnets are opposing magnets and attraction in the opposite case. For magnetization parallel to a plane, there is either repulsion and moment if the magnets are in the same direction, or attraction if they are in opposite directions.

In the case of magnets, the layers may be formed of magnetic materials such as FePt and/or CoPt and/or SmCo and/or NdFeB, which may be deposited as is or in the field or then obviously polarized by electroplating, physical deposition (triode sputtering, pulsed laser or other methods) or other means, or may be magnetized immediately upon deposition or subsequently, for example by thermal annealing or in a laser beam sub-field or other means. The polarization may be primarily in the plane of the layer or in a plane perpendicular to the layer.

In a third embodiment, which is more complex to implement, the thin layer is charged and magnetized simultaneously.

In an advantageous variant, the active layer or the electrically and/or magnetically active layer may be covered with a friction layer. This solution is advantageous in that the contact is not completely eliminated, but a very low level of contact force is maintained. In particular in the case of timepiece escapements, this method greatly improves the efficiency of the escapement by reducing friction compared to the usual embodiments. For example, a silicon oxide escapement covered with a material with advantageous suitable tribological properties, such as diamond-like carbon (DLC), has a completely satisfactory behaviour and increases efficiency.

The depth at which the electrochemically and/or magnetised active layer is located at the outermost of one of the cooperating surfaces is preferably small, typically between 0.1 μm and 5 μm, so that the force is effective, but the depth must be sufficient for the friction layer to withstand natural wear.

The thickness of the above-mentioned thin layer is less than 100 μm and preferably between 0.1 and 20 μm. Naturally, the overall thickness of the thin layer between the two opposite members must remain kinematically compatible, not exceeding the working gap between them, and preferably remaining less than half the value of the above-mentioned gap under most adverse conditions.

The surface area of the layer naturally depends on the component on which the treatment is carried out and on the type of deposition. According to a particular case, the layer may advantageously be divided into a plurality of islands. For example, for embedded polysilicon systems, it may be advisable to laterally partition the charge reservoir formed by the polysilicon islands in order to improve efficiency in the event that a portion of the charge reservoir leaks (charge is lost). For horological applications, the maximum dimension of the surface area of the active layer or of the islands when the layer is thus divided into islands is preferably between 0.01mm and 1 mm. In practice, island sizes between 0.01mm and a few millimeters are generally suitable, provided of course that the repulsion is proportional to the surface area involved.

The base material of the component to which the thin galvanic and/or magnetized layer is applied and which may itself be protected by an external friction layer may be one of the materials used or under development by the watchmaking industry for timepiece applications: single crystal silicon, single crystal quartz, polycrystalline silicon, metals, metal alloys, ceramics, plastics, glass, amorphous materials, amorphous metals, "LIGA". The above examples are not limiting.

In the case of electrets, for example, thin layers may be provided locally on the member in order to extend the life of the product.

Magnetic repulsion may also be present if one of the two opposing members is in a diamagnetic state and if only the other of the two opposing members has at least one magnetized layer. The method for manufacturing a transmission with reduced or no contact in a timepiece movement is therefore characterized in that: the manufacture or modification of at least one pair of opposite surfaces of said timepiece movement is achieved by implementing a surface treatment or an integral treatment on one of the opposite cooperating surfaces to impart a magnetic charge thereon, the other of said opposite surfaces being in a diamagnetic state in which one surface drives or abuts the other surface such that they tend to repel each other as said opposite members move closer to each other.

In a particular embodiment, the polysilicon layer embedded in the oxide is charged in a similar manner to an EEPROM type electronic memory.

Although the invention is preferably designed to be applied to a pair of opposed members, it may also be applied to a single independent member in the nature of a process using a thin galvanic or magnetising layer which cooperates with an opposed member which does not receive the same thin galvanic or magnetising layer process, but which is wholly subjected to a more conventional galvanic or energised current, or which is wholly magnetised or under the influence of a magnetic field generated by a magnet or current.

For example, the situation may more particularly relate to a shaft or spindle on which the treatment method using the charged or magnetized lamina according to the invention is applied, which cooperates with a large solid part subjected to galvanic and/or magnetization, such as a plate or bridge. Preferably, in timepieces containing a large number of components sensitive to magnetic fields that disturb the speed and regularity of the movement, it is preferable to give the solid part electrodes instead of the magnetic poles and therefore to choose a thin strip electrical layer treatment for the relative axis or arbour.

The application of the invention to a spindle and bore pair is particularly advantageous as it enables the elimination of a pivot or the manufacture with smaller dimensions, since very low residual contact stresses are achieved by the invention. It is advantageously possible to vary a large number of clockwork mechanisms, including blind or machined, in a member made of electromagnetic material without varying their dimensions, and to polarize and/or magnetize said clockwork mechanism so as to repel a spindle having the same polarity or magnetism, both radially and axially, at the end of the spindle, which means that the spindle can remain suspended in its housing.

Advantageously, the member or pair of members comprising the opposite surfaces is made of a micromachinable material obtained with MEMS technology or of silicon or quartz or of a material manufactured by the LIGA method. In fact, these materials are preferably used because they have a lower inertia than steel or other alloys, and moreover, these supporting materials are particularly suitable for fixing the thin layer according to the invention.

In an advantageous variant, the micromagnets are made by lithography or within a structure made by lithography.

In particular, at least one pair of opposite cooperating surfaces of the same member or of a pair of opposite members is modified or manufactured by carrying out a surface treatment with a thickness less than or equal to 20 μm.

The invention also concerns a timepiece movement including at least one pair of opposed members, one of which drives the other or abuts against the other, said pair of members being made or modified by implementing the method described above.

The present invention provides the following advantages: when the thickness of the thin layer is very small, preferably much smaller than the working gap between the surfaces or between the opposing members, it is made possible to keep the original dimensions of the respective members unchanged. The implementation of the invention improves the overall efficiency of the timepiece movement and allows to increase the power reserve of the movement or to use a barrel or energy storage device of smaller size, so as to obtain a more compact movement, in particular for use in lady watches.

It is clear that, depending on the dimensions of the laminae and on the level of their electrical and/or magnetic activation, the stress actuators in the movement can achieve, as an ideal case, a true lack of contact at each pair of opposite members involved, or a much reduced contact compared to the same movement with the same kinematic chain, to which the method of the invention has not been applied. In all cases, as a result of the invention, considerable savings are made in terms of friction, energy and wear.

The repulsion phenomena between the components also allow to absorb certain shocks or impacts, which also allow to reduce wear and to prolong the life of the movement, and in particular to be consistent in performance over time.

Naturally, the above features apply to the opposite problem when seeking to attract opposite surfaces to each other.

In particular, by arranging the opposing surfaces to attract each other, mechanical play in a transmission or the like can be taken up.

This arrangement may be advantageous in situations where the operation of the mechanism requires an impact, such as a hammer impact heart, a jumper impact star wheel or calendar disc or in a striking mechanism or similar, and after said impact the attractive force generated by the electret or magnetized surface returns the relevant components to their position, especially without any play. Thus, the application relates in a non-limiting manner to the control of clearances and frictional forces in certain mechanisms.

It is thus clear that the invention enables control of the friction forces, both in the sense of reducing or eliminating said forces, and in the sense of stabilizing or increasing said forces.

The invention is of course not limited to the examples shown but comprises numerous variants and modifications apparent to the person skilled in the art.

Claims (20)

1. A method for manufacturing a transmission device with controlled or reduced contact or no contact in a timepiece movement, characterized in that at least one pair of opposite surfaces of the same member or of an opposite pair of pivotal members of said timepiece movement is made or modified by subjecting at least one of said opposite surfaces forming said pair of pivotal members to a surface treatment or an integral treatment to impart thereon at least an electrostatic charge, said opposite surfaces being called cooperating surfaces, wherein one of said opposite surfaces drives the other or is in close proximity to the other, so that one of said opposite surfaces tends to repel the other of said opposite surfaces when said opposite surfaces are moved closer to each other.

2. The method of claim 1, wherein making or modifying the at least one pair of opposing surfaces of the same member or an opposing pair of pivotal members is accomplished by subjecting the opposing surfaces to a surface treatment or integral treatment to impart electrostatic charges of the same polarity such that they tend to repel each other as the opposing surfaces move closer to each other.

3. The method of claim 1, wherein each of the opposing surfaces is subjected to a surface treatment or an integral treatment when the opposing surfaces are manufactured or modified.

4. A method according to claim 3, characterized in that when the opposite surfaces are surface-treated, each of them is covered with at least one thin layer of charged particles of the same polarity as each other, called activation layer, so that when the opposite surfaces are moved closer to each other they tend to repel each other, or at least one such thin activation layer is created.

5. A method according to claim 3, characterised in that, when the opposite surfaces are subjected to the overall treatment, a part of the structure of each member concerned is subjected to an electrochemical treatment on at least one thin layer, called activation layer, which after the electrochemical treatment comprises charged particles having the same polarity as each other, so that when the opposite surfaces are moved closer together they tend to repel each other or to create at least one such thin activation layer.

6. A method according to claim 3, wherein one of the opposing surfaces is subjected to a surface treatment and the other of the opposing surfaces is subjected to an integral treatment.

7. The method according to claim 1, characterized in that the surface treatment consists in: a plurality of thin layers of pairs of charged particles of the same polarity are created or deposited on each of the opposing surfaces such that they tend to repel each other as the opposing surfaces move closer to each other.

8. The method according to claim 1, characterized in that the overall process consists in: subjecting a portion of the structure of each member concerned to an electrochemical treatment on a plurality of thin layers comprising pairs of charged particles of the same polarity after the electrochemical treatment such that they tend to repel each other as the opposing surfaces move closer to each other.

9. A method according to claim 1, characterized in that at least one of said opposite surfaces comprises at least one thin layer of charged particles, called activation layer, which is activated after deposition on said at least one surface to impart the desired polarization thereon.

10. Method according to claim 1, characterized in that at least one of said opposite surfaces comprises at least one layer of charged particles, called active layer, which is SiO on a silicon substrate₂An electret.

11. Method according to claim 1, characterized in that at least one of said opposite surfaces comprises at least one thin layer of charged particles, called activation layer, the outermost electrochemically active layer of one of said opposite surfaces being located at a depth between 0.1 μm and 5 μm below the friction surface layer.

12. A method according to claim 1, characterized in that at least one of said opposite surfaces comprises at least one thin layer of charged particles, called active layer, the maximum surface area size value of which or when said layer is divided into islands, the maximum size of said islands is between 0.01mm and 1 mm.

13. Method according to claim 1, characterized in that at least one of said opposite surfaces comprises at least one thin layer of charged particles, called active layer, having a thickness less than or equal to 20 μm.

14. Method according to claim 1, characterized in that at least one of said opposite surfaces comprises at least one thin layer, called activation layer, of charged particles, set and activated by means of electrochemical application in an electric field or by means of ion or electron injection or by means of a "corona" method, so as to generate a charge of at least 0.1mC/m²And 50mC/m²Surface charge density of (d).

15. Method according to claim 1, characterized in that at least one of said opposite surfaces comprises at least one thin layer of charged particles, called activation layer, which is galvanic and made of SiO2 or As2S3 or fluorinated polymers or teflon orOr paryleneAnd (4) forming.

16. Method according to claim 1, characterized in that at least one of said opposite surfaces comprises at least one thin layer of charged particles, called active layer, which is galvanic and where an electrostatic charge is placed embedded in an insulator or SiO in the form of islands of any size₂The islands are formed by photolithography.

17. Method according to claim 1, characterized in that the member or the pair of pivoted members comprising the opposite surfaces is made of a micromachinable material obtained with MEMS technology or of monocrystalline silicon or monocrystalline quartz or of polycrystalline silicon or of a material manufactured by the LIGA method.

18. Method according to claim 1, characterized in that the at least one pair of opposite surfaces of the same component or of an opposite pair of pivoted components is modified or manufactured by applying a surface treatment with a thickness of less than or equal to 20 μm.

19. A timepiece mechanism including at least one opposed pair of pivotable members, one member of the opposed pair of pivotable members driving or being supported by the other member, the opposed pair of pivotable members being manufactured or modified by carrying out the method according to claim 1.

20. The clockwork mechanism of claim 19, wherein said pair of opposing pivotal members are:

two gears;

two cams;

a cam and a swing lever;

two oscillating levers;

a spindle or shaft and a pivot;

a pallet fork and an escape wheel;

a pallet fork and a balance roller;

wheels and whips;

a heart cam and hammer; or

A spider and fingers.